1. Field of the Invention
This invention relates generally to a process for manufacturing carriers for semiconductor devices such as integrated chips and particularly relates to such a process for manufacturing the bump circuits of such carriers.
2. Description of the Prior Art
It is well known to provide carriers for semiconductor devices such as integrated circuit chips. Such carriers usually have a lead circuit represented by one surface of the carrier while the opposite surface is provided with bumps or pads for making contact with the conductive terminals of the semiconductor devices. Examples of such carriers are shown in the patent to Aird, U.S. Pat. No. 3,689,991 and in the patent to Galli et al., 3,781,596.
As disclosed by way of example in these patents, the carrier is provided with bonding pads or bumps which serve the purpose to connect the carrier to the conductive terminals of the semiconductor devices. The carriers are usually in the form of tapes and may be provided with longitudinally spaced apertures or sprocket holes for purposes of registration. The pads are bonded to the terminals or contacts of the semiconductor devices by a thermal bonding process, also described in the patent to Aird, above referred to.
In order for the thermal bonding device to pass through the carrier, a suitable aperture is provided in the carrier adjacent the bumps.
It has been found in the past that it is difficult to control the relatively small size of the bumps which may be on the order of 3 mils or less in diameter. This is particularly difficult with conventional chemical etching, which not only takes place both from the lead circuit side and the bump circuit side. Also it has been found that the leads become so thin that they are liable to break, either during use or while being subjected to pull tests.